The prior art shows a number of fire retardant devices or fittings for the installation of electrical, communications and related wiring connections through a fire retardant floor. These fittings are designed to maintain the fire rated capabilities of the floor, so that the fire rating is substantially the same as if the hole and fitting did not pass through the floor. Examples of such fittings are described, inter alia, in U.S. Pat. Nos. 5,393,930; 5,696,349; 5,763,826; and 5,814,764.
These and other prior art references utilize a conduit for carrying the wiring through the fire rated floor, said conduit generally attaching to a floor mounted box at or above the top surface of the floor and a junction box located below the floor. The conduit is generally surrounded by elements sized to fit substantially within a through hole in the floor, the standard poke through holes having a 3 inch or a 4 inch diameter. To maintain a fire rating, it is known in the prior art to use fire barriers in the portion of the through holes surrounding the conduit.
It has been shown that the most preferred fire barriers currently used in poke through fittings have been intumescent materials that swell or expand during high temperature conditions. In the event of fire the high temperatures cause the intumescent materials to expand to fill any openings in the floor, thereby inhibiting the spread of smoke and fire to adjacent floors.
However, current fire retardant poke-through fittings are generally multi-component devices which require complex manufacture, are inefficient for use across a variety of conditions commonly found in the field and are challenging to properly install. For instance, the lower intumescent portion of the device of U.S. Pat. No. 5,814,764, as best seen in FIG. 4 of that patent, would be wasted when used with a thinner floor. In another example, the device of U.S. Pat. No. 5,393,930 requires that the lower intumescent portion be manually positioned at the lower edge of the floor and securely tightened using set screws.
It is therefore an object of the present invention to provide a fire retardant poke-through device that efficiently uses intumescent materials and reduces the human error involved in the proper location of the lower intumescent material. It is a further object of the present invention to provide such a poke-through fitting which is easily manufactured with a limited number of parts.